1. Field of the Invention
The present invention relates to the production of structural and/or decorative parts made of plastics materials. More particularly, it relates to composite parts having at least one portion that is foamed in situ and covered with a skin or the like.
2. Related Technology
The present invention relates to a method for producing a composite part, and a composite part obtained by this method, in particular a structural and/or decorative part that is intended to be fitted inside a motor vehicle.
The invention aims to provide a solution for decorating or modifying, in surface regions, a base body or element made of a rigid material, by attaching to it a soft or resilient coating, forming padding, said additional coating comprising a foam body covered with a skin or similar finishing layer.
It is thus possible to provide rigid plastics material elements or portions with decorative and/or practical elements or parts, which differ not only in terms of visual appearance and feel, but also in terms of texture, mechanical characteristics (deformation) and thermal characteristics (insulation).
One way of industrially producing composite parts of this type is locally foaming a suitable foaming material in a mould, between the base body or substrate, which is made of a rigid material provided with a depression or a recess, and the covering or finishing skin, layer or element.
The two fundamental problems encountered in the implementation of this method are those of preventing foaming material from escaping at the edges of the skin or similar covering element (see the cross-sections of FIGS. 1a and 1b of the accompanying drawings) and providing the interface between visible face of the rigid material part and the skin-covered foam forming the decorative zone with an optimal appearance. In the past, various solutions have been proposed in an attempt to solve the two aforementioned problems.
A first know solution involves producing a recess in the region of the interface zones of the base body or substrate made of rigid material, the recess being intended to receive the edge of the covering or finishing element forming skin. Nevertheless, this solution does not obtain an optimal and systematic tightness between the base body and the skin.
A second known solution involves providing the edges of the coating element and the corresponding interface zones of the base body or substrate with specific mutually complementary shapes, so as to form a chicane in a result of the cooperation of these complementary shapes, with a supplementary part optionally being fitted. Nevertheless, this second solution requires the coating element to be positioned extremely precisely relative to the base body, so that supplementary movable holding means also have to be used, and makes the base body more complex to produce. Furthermore, this solution cannot be carried out in specific configurations or constructions and can make the structure of the mold considerably more complex.
A third solution includes fitting an adhesive in the region of the interface zone of the base body, so as to retain the edges of the covering element during foaming. This entails additional labor and expense (application of the adhesive) and optimal tightness cannot be guaranteed.
The aim of this invention is, in particular, to overcome the limitations of the above-mentioned solutions.